Additives impart special qualities to fuels and lubricants, providing new properties or enhancing those already present. The use of polyalkylene amines in fuel compositions as detergents is well known. They are effective in maintaining the cleanliness of the mixture formation and intake systems of gasoline engines (i.e., carburetor, injection nozzles, intake valves and mixture distributor), since they enable fuels to decompose cleanly at high temperatures leaving little or no residue. Fuel additives also reduce emissions from internal combustion engines. Polyalkylene amines have also been used as dispersants and detergents in lubricants, in which they impart cleanliness and stability at high temperatures. Polyalkylene amines have generally been used as dispersant and detergent additives. Other additives have been necessary to impart antiwear and corrosion-inhibiting properties to the fuel or lubricant, such as low molecular weight sulfur-containing heterocyclic additives. The beneficial effects of the product of the instant invention are believed to be the result of an internal synergism between the polyalkylene amine groups, and the heterocyclic groups containing sulfur and nitrogen. The additives of this invention show good thermal decomposition, oxidative stability, and compatibility with other commonly used fuel or lubricant additives when admixed with them. They are effective performance enhancers in either fuel or lubricant compositions.